EDPR will next month switch over to energy availability-based service contracts at five Portuguese wind farms, drawing from in-depth, granular cost assessments and five years of SCADA data, Pedro Alves, EDPR's Transversal Activities Manager, said.

The removal of wind subsidies and the introduction of competitive wind power tenders are accelerating cost reductions and putting increasing pressure on operations and maintenance (O&M) efficiency.

Wind operators are increasingly seeking service contracts based on energy availability, which measures how well a wind farm captures available wind resources, rather than time-based availability metrics.

From April, renewables group EDP Renovaveis (EDPR) is to implement its first energy availability-based wind service contracts, following almost 10 years of studies, Alves told the Wind O&M EU 2018 conference on February 14.

EDPR currently operates around 11.2 GW of wind power capacity, including over 5 GW in both Europe and the U.S.

Based on technical energy availability (TEA), the new contracts will cover five EDPR wind farms in Portugal, representing a total capacity of 250 MW. Two of these windfarms use Vestas turbines and three use Izar Bonus models. The ages of the windfarms range between 11 and 20 years.

Energy-based key performance indicators (KPIs) allow operators to refine business plans and budgets while providing more reliable information internally and to the markets, Alves told attendees.

The focus on maximising energy availability typically results in longer maintenance windows, enabling staff to perform work of higher quality, he said.

Energy availability contract terms improve O&M cost efficiency by incentivising service providers to focus on energy losses and be more flexible in the distribution of resources, Alves said.

Service providers effectively receive a small percentage of generation revenues, and penalties apply if the service provider falls below energy availability targets.

“The KPI we chose for this contract this year is 98% energy availability,” Alves said.

In-depth assessment

The switch to energy availability requires significant resources and operators must decide on a case-by-case basis whether the benefits will outweigh the costs.

"We have to have information like price in the contracts...which infrastructures and investments are needed internally, and more importantly, what is the goal of the owner," he said.

For its five chosen Portuguese windfarms, EDPR transferred five years of data from Supervisory control and data acquisition (SCADA) systems to its Open Platform Communications (OPC) system.

To perform a full cost assessment, each downtime event and status indicator must be allocated to a specific downtime category, Alves said.

"The difficult part of all this process is to uniformize all the data that you have and to really define correctly all the events and status. If you don't do that, at the end the information that you get will be bad information and probably will make you take wrong decisions, he said.

EDPR ranked the different methods of calculating downtime losses in order of preference. The priority method would be to use Nacelle reference power curve data and if this information is not available then the company would use output evaluations for neighboring turbines. If this data is not available, met tower reference power curve data would be the next preference, followed by evaluations of partial production meter data.

Staff challenges

Internal human resources must also be re-evaluated to implement energy availability KPI’s. Once operational, energy availability strategies require additional resources from operators and service providers.

"We need to maintain, audit and improve the system, and also have someone verify the calculations," Alves said.

Under this approach, accurate wind form forecasts are critical and maintenance teams must be trained to respond to the latest data.

"It's a mindset change...this information has to be reliable and each wind farm manager has to receive this information, check it and they should re-plan all of the works, regarding the information they receive," Alves said.

Energy availability strategies can also create a divergence of data held by operators and service providers, which can increase the time required to agree contracts, he noted.

While service providers face similar staff resource and training challenges as operators, changes in labor strategies can represent an opportunity for companies, Alves said.

"Even though the service provider will have more tasks, the reality is that due to the high flexibility of these type of contracts, they can reduce the number of teams in the field and with that they can reduce their costs and we can reduce our costs in the contracts," he said.

New benchmark

Given the significant cost requirements associated with changing from hourly availability to energy availability, this approach may only be economical for larger operators, Alves said.

In addition, long-term full-scope contracts may prevent operators from switching to energy availability KPIs for some time.

EDPR's switch to energy availability is currently limited to a small amount of Portuguese windfarms, due to long-term contracts signed with suppliers at other sites.